Connection element, method for manufacturing a connection element and related installation kit

ABSTRACT

A connection element (12) made of composite material includes a bundle of fibers (13) and a binding agent, and has at least one preformed portion (14) and at least one free fiber portion (16, 18, 19). The at least one preformed portion (14) includes a section of fibers (13) embedded in the binding agent to form a monolithic structure. At least part of the fibers (13) of the at least one free fiber portion (16, 18, 19) has virgin fibers (13).

FIELD OF APPLICATION

The present invention relates to a connection element, a method formanufacturing a connection element and a related installation kit. Inparticular, the present invention relates to connection elements made ofcomposite material to be used, for example, for consolidating orimproving the safety of structures in the building industry and in theindustry in general.

BACKGROUND ART

As known, there are many techniques for consolidating architecturalstructures or the safety thereof. In particular, there are techniqueswhich use rigid meshes made of composite material made with fibresincorporated in a thermosetting resin.

In some applications, the meshes are embedded inside a mortar withbinding agents, which may be of different types, and are used forconsolidating existing structures (masonry, concrete, reinforcedconcrete, etc.) creating a reinforced plaster to be applied on thesurfaces, or as slabs for manufacturing load bearing floor slabs.

The mesh, for example, may be blocked in position by means of the use ofjunction elements inserted in holes made in the masonry. The junctionelements are generally made of metal or another material, and have anL-shape, in which the two sides are substantially perpendicular to eachother. In use, once an anchoring resin has been distributed inside thehole, one side is inserted into the hole obtained in the masonry, whilethe other side is arranged parallel to the surface of the masonry. Meshand junction elements are therefore embedded inside a mortar withbinding agents which may be of different types.

If the mesh is positioned on both surfaces of a masonry, it is possibleto block it in position, making a through hole so that the two meshesmay be connected to each other with two junction elements: a firstjunction element inserted at one surface, and a second junction elementinserted at the opposite surface.

As an alternative to the type of junction elements mentioned, junctionelements made with preformed bars made of composite material comprisingfibres and thermosetting resin are known.

The preformed bar made of composite material may be obtained by means ofa forging method or by means of a pultrusion method. In both cases, thefibres are picked up and passed through a resin impregnation bath.

In the moulding process, the impregnated fibres are modelled directly onthe die, where they are subjected to natural or artificial curing insuitable furnaces.

In the pultrusion process, at the exit of the area in which theimpregnation occurs, the impregnated fibres pass through a die so as togive the manufactured item a specific cross section, compacting thefibres together. The impregnated fibres are then passed inside a curingfurnace which provides heat so that the resin may polymerize andtherefore cure. These two steps may be carried out jointly in theproduction die.

Downstream of the plant, a so-called pulling device is there, whichprovides the impregnated fibres with the traction necessary to movethrough the stations mentioned above.

The method is therefore free from downtime, since the pulling deviceallows the manufactured item being processed to move between the variousstations of the apparatus.

Downstream of the pulling device, an area may be arranged for theautomated cutting of the pultruded bars.

Bars made of composite material offer many advantages. For example, withrespect to bars made of metal, they are lighter and are not subject tooxidation.

The main limitation of the pultruded bars is that they may not be benton site, for example in the case in which an anchorage is to be madethrough the masonry between two reinforcement plates.

The only way to obtain bent bars made of composite material is toproduce them directly bent by means of forging, in a dedicated plant.However, the production of these elements, even if they are manufacturedalready bent, fails to ensure the dimensional and inclinationflexibility which would instead be necessary.

To establish a connection between the two reinforcement areas, or simplyto perform the function thereof as a connector, it is thereforenecessary to use two distinct L-shaped elements, then joined by means ofan overlapping of the chemical or mechanical type, at the portionsthereof, inside and not crossing the structural element.

Furthermore, in the case of L-shaped connectors, precisely at theconnecting portion between the two sides of the L, a decrease inresistance and stiffness is there, with respect to the straight section.

The prior art has attempted to solve this issue by proposing pultrudedbars subjected to a processing by means of which the fibres at one endof the bar are freed from the already cured resin.

The end of the bar, after the pultrusion process, is subjected to asolvent bath and/or a pyrolysis at a temperature to eliminate theresinous matrix and keep the fibre dry.

The bars thus obtained may be inserted inside a hole made in the supportto be reinforced or positioned where previously defined, while the endconsisting of free fibres (called, in the technical jargon, theunravelled end) is radially widened and glued to the desired surfacewith specific organic and/or inorganic adhesives or embedded in themortar with which the surface of the support is coated. Thereby, theunravelled end ensures the mechanical continuity of the elements.

The procedure used to free the fibres from the resin, however, has somedisadvantages.

In the first place, it is a further processing which must be carried outon the bar, and therefore affects the production costs and the timerequired for the production of the preformed connector.

Furthermore, the fibres which are freed from the cured resin have worsemechanical features with respect to the intact bar, but also withrespect to the fibres before the impregnating step, since theinvasiveness of the process modifies the structure of the fibre and thepriming thereof, the lubrication and assembly thereof, substantiallyremoving the gripping power of the free and dry end.

PRESENTATION OF THE INVENTION

Therefore, the need is felt to solve the drawbacks and limitationsmentioned above with reference to the prior art.

Therefore, the need is felt to provide a connection element for thebuilding industry and industry in general, which may be adapted todifferent conditions of use.

Furthermore, the need is felt for a connection element for the buildingindustry which may be easily used for the junction through a throughhole in the support to be consolidated by means of reinforcement plateson the surfaces thereof, or simply as a connection element with the endsto be embedded in two or more solids to be connected.

Furthermore, the need is felt for a connection element for the buildingindustry which is simple and cost effective to manufacture with respectto preformed connectors of the known type.

Furthermore, the need is felt for a connection element which is easierto use with respect to the connectors of the prior art.

Such needs are at least partially met by a connection element accordingto claim 1, by a method for manufacturing a connection element accordingto claim 11, and by a related installation kit according to claim 14.

DESCRIPTION OF THE DRAWINGS

Further features and advantages of the present invention will be morecomprehensible from the following description of preferred embodimentsgiven by way of non-limiting examples, in which:

FIG. 1 diagrammatically shows a perspective view of a first embodimentof a connection element according to the present invention;

FIG. 2 diagrammatically shows a perspective view of an alternativeembodiment of a connection element according to the present invention;

FIG. 3 diagrammatically shows a perspective view of a furtheralternative embodiment of a connection element according to the presentinvention;

FIG. 4 diagrammatically shows a possible use of a connection elementaccording to the present invention;

FIGS. 5-7 diagrammatically show perspective views of possibleembodiments of a connection element according to the present invention;

FIG. 8 diagrammatically shows a possible alternative embodiment of aconnection element according to the present invention;

FIG. 9 diagrammatically shows a possible alternative embodiment of aconnection element according to the present invention;

FIG. 10 diagrammatically shows a possible alternative embodiment of aconnection element according to the present invention;

FIG. 11 diagrammatically shows a perspective view of a component of akit according to the present invention; and

FIG. 12 diagrammatically shows a sectional view of a component of a kitaccording to the present invention.

Elements or parts in common to the embodiments described will beindicated hereafter using the same reference numerals.

DETAILED DESCRIPTION

FIG. 1 shows a connection element according to the present invention,which is indicated with the generic reference 12.

The connection element 12 is made of composite material comprising abundle of fibres 13 and a binding agent. The binding agent may be aresin or an inorganic matrix.

In this disclosure, the term matrix and the term binding agent will beused indifferently to indicate the same material.

In particular, the connection element 12 comprises at least onepreformed portion 14 and at least one free fibre portion 16, 18.

The preformed portion 14 comprises a section of the bundle of fibres 13embedded in the binding agent to form a monolithic structure.

In particular, the preformed portion 14, which in use may be insertedinside a hole in the support to be consolidated or in the solids to beconnected, may have an external surface with sand or grit and bindingagent fillings, or an external surface subjected to roughing by means ofa mechanical processing, by removing material or by forging, in order toimprove the performance of the connection.

The length of the preformed portion 14 may, for example, range from 10mm to 20000 mm. In any case, the length of the preformed portion 14 maybe adapted to specific needs.

Advantageously, the length of the preformed portion 14 may be decided onthe basis of the thickness of the structural or non-structural elementcrossed and/or the distance of the elements to be connected in which itmust be inserted.

The preformed portion 14 may have a substantially circularcross-section, as shown in the embodiments of FIGS. 1, 2, 3, 8-10 .

According to a possible alternative embodiment, shown in FIG. 5 , thecross section of the preformed portion may be C-shaped.

In a possible alternative embodiment, shown in FIG. 6 , the preformedportion 14 may have an elongated cross-section, even with or without thepresence of a reinforcing rib 21, having a longitudinal or transversedevelopment. In the embodiment shown in FIG. 6 , the reinforcing ribs 21are two and arranged parallel.

In a further embodiment, the preformed portion may have a substantiallycircular and hollow section, as shown in the example of FIG. 7 .

The cross section may, for example, be T-, L-, C-, double T-shaped,rectangular, square, cylindrical or according to specific designrequirements.

Advantageously, in the case where the section of the preformed portion14 is hollow, the internal volume of the preformed portion 14 may befilled to increase the resistance, or in general the performance,thereof. The internal volume may be filled, for example, with resins,mortars, organic or inorganic matrices or matrices of another type.

The external surface may be continuous, provided with holes or subjectedto other surface treatments capable of improving the adhesion of theconnection element.

The free fibre portion 16, 18 may be arranged at one or both ends of thebundle of fibres 13. Embodiments of this type are shown for example inFIGS. 1 and 2 .

According to a possible embodiment, the free fibre portion may bearranged between two preformed portions 14. An embodiment of this typeis shown in FIG. 3 .

In particular, the length of the free fibre portion 16, 18 may, forexample, range from 10 mm and 20,000 mm.

In any case, the length of the free fibre portion may be adapted tospecific needs.

At the free fibre portion 16, 18, 19, at least one part of the fibres 13consists of virgin fibres.

In this disclosure, the term virgin fibres means fibres which, at aportion thereof, have not been embedded in the resin, mortar, organicmatrix, inorganic matrix, or matrix of another type. In technicaljargon, virgin fibres may also be defined as dry fibres.

In particular, virgin fibres are fibres which, in the free fibre portion16, 18, 19 have not been embedded with resin, mortar, organic matrix,inorganic matrix or another matrix to make a monolithic or preformedstructure.

In other words, the fibres 13 which form the connection element 12 havebeen impregnated at the preformed portion 14, while they have not beenimpregnated in the free fibre portion 16, 18, 19.

In any case, as it will be obvious to those skilled in the art, suchfibres may, for example, be processed or treated in line or during asubsequent step to obtain products or elements with shape and featuresbased on the specific function thereof, such as, for example, thepossibility of impregnating with matrices and/or gripping material withdifferent properties.

In other words, the free fibre portion 16, 18, 19 may comprise orconsist of virgin fibres.

According to a possible embodiment, advantageously, the free fibreportion 16, 18, 19 may be made with at least 90% of virgin fibres.

FIG. 4 shows some examples of installation of connection elements 12according to the present invention, in which the free fibre portion 16is visible, the fibres 13 of which are arranged radially.

According to alternative embodiments, the fibres of the free fibreportion 16, 18, at the ends, may also be arranged in different manners,as it may be easily assumed by those skilled in the art.

According to a possible embodiment of the present invention, the freefibre portion may consist of virgin fibres.

The bundle of fibres 13 may comprise synthetic organic fibres, naturalorganic fibres, inorganic fibres, and/or metallic fibres.Advantageously, a connection element may comprise fibres of a differenttype.

The synthetic organic fibres may comprise, for example, aramid fibres,poly-para-phenyl benzobisoxazole (PBO), and/or polyester.

Natural organic fibres may comprise, for example: cotton, hemp, flax,sisal, bamboo, wood, wool, silk, etc.

The inorganic fibres may comprise, for example: glass, carbon, basalt,quartz, etc.

The metallic fibres may comprise, for example: stainless steel, carbonsteel, copper, brass, aluminum, titanium, etc.

According to a possible embodiment of the present invention, the bundleof fibres 13 may comprise fibres of different type.

According to a possible embodiment, the binding agent may be a resin.

As for the resin, this may be of the thermosetting type, of thethermoplastic type, it may use inorganic matrices and/or matrices ofanother type.

In the case of thermosetting resin, this may, for example, be of thevinyl-ester, polyester, bisphenol, acrylic type, etc.

In the case of thermoplastic resins, the resin may be selected from thegroup comprising PVA, PP, Pen, etc.

In the case of inorganic matrices, the matrix may be cement, quartz,lime, gypsum, etc.

According to a possible embodiment of the present invention, theconnection element 12 may comprise a guide element 24 (shown in FIG. 8 )sliding within the preformed portion 14, so as to be adapted to be movedbetween an extracted position, protruding from the preformed portion 14at the at least one free fibre portion 16, 18 and a retracted positionin which it does not protrude or protrudes from the preformed portion 14at the at least one free fibre portion 16, 18.

The guide element 24 may be made of rigid polymeric material. Forexample, the guide element 24 may be made of thermoplastic,thermosetting, metallic material, etc.

According to an alternative embodiment, the guide element 24 protrudesfrom the preformed portion 14 at the at least one free fibre portion 16,18, but it does not slide inside the preformed portion 14.

The guide element 24 is used to optimize the unravelling of the at leastone free fibre portion 16, 18 of the ends of the connection element 12.

According to a possible embodiment of the present invention, the freefibre portion may comprise a grouping element 26 in a positionsubstantially distal with respect to the preformed portion 14.

The grouping element 26 is adapted to group the virgin fibres together,in one or more positions of the section distal with respect to thepreformed portion 14. In other words, between the grouping element 26and the preformed portion 14 there is a section comprising or consistingof virgin fibres.

According to a possible embodiment of the present invention, thegrouping element 26 may, for example, be a resin, or a retention elementsuch as, for example, a ring or a device for grouping the fibres made ofplastic material, or of any material durable in time, tightened aboutthe guide element 24.

According to a possible embodiment of the present invention, thegrouping element 26 may slide with respect to the guide element 24. Inthis case, once the preformed portion 14 has been inserted inside thehole obtained in the masonry, the grouping element 26 is made to slideon the guide element 24 which is fixed, so that the virgin fibres arearranged in the desired regular or irregular shape on the surface of thesupport to be consolidated or to be made integral. The excess part ofthe guide element 24, protruding from the surface of the masonry, may becut before or after the adhesive or the matrix has been distributed onthe surface of the support to embed and fix the virgin fibres.

In accordance with a possible alternative embodiment, the groupingelement 26 may slide with respect to the guide element following apredefined arrangement, for example, using a preformed portion 14 havinga helical development.

In this case, once the preformed portion 14 has been inserted inside themasonry, the guide element is made to slide, dragging the groupingelement 26 by means of the movement thereof.

In accordance with a possible embodiment, the grouping element 26 mayalso be rotated about the main axis.

According to a possible embodiment, a free fibre portion 19 may bearranged between two preformed portions 14. In other words, thepreformed part may comprise at least two monolithic sections separatedfrom each other by a section at least partially made with virgin fibres.Advantageously, it is therefore possible to make the connection element12 maintaining one or more intermediate dry portions, for example, bymeans of a pultrusion process interrupted by bath or by impregnation. Inthis specific case, the use may be extended to the creation of realbrackets of elements to be consolidated, keeping the dry section in thepositions in which the preformed sections may not be used.

According to a possible embodiment of the present invention, said virginfibres may comprise impregnation points 30, adapted to improve the gripof the virgin fibres in the binding agent used to cover the surface ofthe masonry.

A method for making a connection element 12 made of composite materialcomprising fibres and a resin-based binding agent according to thepresent invention will be described below.

The method comprising the steps of:

-   -   providing a bundle of fibres 13;    -   impregnating the fibres 13 with a binding agent;    -   passing the impregnated fibres 13 inside a die having a certain        cross-section;        -   curing the resin inside a curing furnace or the die itself;            and        -   cutting the connection element.

In particular, the step of impregnating the fibres 13 may occur by meansof a binding agent such as a resin of the thermosetting or thermoplastictype, or an inorganic matrix.

In particular, the impregnation is carried out at sections of the bundleof fibres 13, while in some sections the fibres of the fibre bundlecomprise or consist of virgin fibres.

According to a possible embodiment of the present invention, the cuttingmay occur at a section of the bundle of fibres 13 impregnated withresin, or at a section of the fibre bundle in which the fibres compriseor consist of virgin fibres.

According to a possible embodiment of the present invention, the methodmay comprise a step in which the element 24 is provided inside the fibrebundle.

According to a possible embodiment of the present invention, the methodmay comprise a step in which the grouping element 26 is provided.

The present invention also relates to an installation kit comprising aninsertion funnel 40 adapted to facilitate the insertion of theconnection element 12 inside a hole in a masonry. Advantageously, theinsertion funnel may comprise a tubular portion 44 at one end of which aflaring 42 is provided.

Advantageously, the insertion funnel may also be used to guide thevirgin fibres of the free fibre portion at the curving area on thesurface of the masonry.

The advantages which may be achieved by a connection element accordingto the present invention are therefore apparent.

First, a single connection element has become available, which may beused to connect two plate-like resistant elements through a hole in amasonry. In this case, the ends of the connection element are bothprepared with a free fibre portion.

The virgin fibres are therefore modelled and embedded in the resin or inthe cement matrix, so as to create an effective anchorage and ensure abetter yield of the tensile connection element.

Furthermore, in the case where the ends of the connection element areboth provided with a free fibre portion, the need to join two L-shapedelements inside the masonry has been eliminated.

The connection element according to the present invention may be used,for example, as a connection system between reinforcement elements forthe wall/resistant element which is required to increase the performanceby means of a symmetrical or partially symmetrical reinforcement layout.

The connection element also acts as a tie rod or bracing, the dryterminals/free ends thereof being possibly made on site with anygeometric shape, by means of pre-moulding in the factory or directpre-application on site, with or without the application of a mat tofacilitate the creation of a junction plate or finally by providing alight primer already in the production step to improve the applicationsteps, with the elements to be braced and/or tied.

Furthermore, it may be used as a continuous or discontinuous bracket orreinforcement in general, for structural or non-structural elements madeof reinforced concrete, completing the construction steps in the factory(co-moulding or similar techniques) or on site.

Furthermore, the particular production method allows to manufacture aproduct which maintains the mechanical resistance and stiffnessproperties of the connection in the anchorage area of the elements to beconnected unaltered.

In order to meet specific needs, those skilled in the art will be ableto make changes to the embodiments described above and/or replace theelements described with equivalent elements without departing from thescope of the appended claims.

1. Connection element in composite material comprising a fibre bundleand a binding agent, said connection element comprising at least onepreformed portion and at least one free fibre portion; said at least onepreformed portion comprising a section of said fibre bundle embedded insaid binding agent to form a monolithic structure; wherein at least partof the fibres of the at least one free fibre portion consists of virginfibres.
 2. Connection element according to claim 1, wherein said atleast one free fibre portion is arranged at one or both ends of thefibre bundle.
 3. Connection element according to claim 1, wherein saidat least one free fibre portion is arranged between two preformedportions.
 4. Connection element according to claim 1, wherein saidbundle of fibres (13) comprises synthetic organic fibres, naturalorganic fibres, inorganic fibres, and/or metallic fibres.
 5. Connectionelement according to claim 1, wherein said binding agent is athermosetting or thermoplastic resin or an inorganic matrix. 6.Connection element according to claim 1, comprising a guide elementsliding within said preformed portion adapted to be moved between anextracted position, protruding from said preformed portion at said atleast one free fibre portion and a retracted position in which the guideelement does not protrude or protrudes from said preformed portion atsaid at least one free fibre portion.
 7. Connection element according toclaim 1, comprising a guide element protruding from said preformedportion at said at least one free fibre portion.
 8. Connection elementaccording to claim 1, comprising a grouping element of said fibres ofsaid free fibre portion, in a substantially distal position with respectto the preformed portion.
 9. Connection element according to claim 8,wherein said grouping element is obtained with a binding agent or aretention element.
 10. Connection element according to claim 9, whereinsaid at least one preformed portion is hollow, and the internal volumeis filled with one or more of resin, mortar, inorganic matrices, organicmatrices.
 11. Method for making a connection element out of compositematerial comprising fibres and a binding agent, said procedurecomprising the steps of: providing a fibre bundle; impregnating thefibres with a binding agent; passing the fibres inside a die having across-section; curing the resin inside a furnace or said die; andcutting the connection element; wherein said step of impregnating thefibres with a binding agent is carried out on sections of the fibrebundles, while in some sections the fibres of the fibre bundle compriseor consist of virgin fibres.
 12. Method for making a connection elementaccording to claim 11, wherein the cutting is made at a section of thefibre bundle impregnated with resin.
 13. Method for making a connectionelement according to claim 11, wherein the cutting is made at a sectionof the fibre bundle where the fibres comprise or consist of virginfibres.
 14. Installation kit of a connection element comprising aconnection element according to claim 1, and an insertion funnel tofacilitate insertion of the connection element into a hole in astructural or non-structural element, and to facilitate arranging thefibre bundle as the free fibre portion.